The exercise programs are designed to help you reach a preset goal by varying the activities you do, how many times you do them and for how long. There are three types of exercise programs; build strength, cut weight and build endurance. There are also two lengths of programs; 30 days and 60 days, they do not however require you to work out every day for 30/60 days straight (although if you wish you can still load up the game and drop in some exercises along the way if you were working towards the 3/7/30/100 day achievements). The game schedules you in rest days and workout days which you must adhere to and also complete each exercise on each day to earn this achievement without failing!
If during one of the exercises you think that you aren’t going to be able to finish it/fail it, simply hit pause and restart it. The x360a forums are littered with users who have finished a program only to find the achievement not popping.
These achievements are not easy but then again neither is getting in shape!